The first Boeing 737 MAX 9 airliner is pictured at the company's factory on March 7, 2017 in Renton, Washington. The 737 MAX 9, which can carry up to 220 passengers, is the second of three variants of the popular single-aisle model.

For Norwegian Air, taking delivery of its new Boeing 737 MAX 8 is another great marketing opportunity. It's offering a dozen people a once-in-a-lifetime ride on the airline's newest plane.

But just four days after opening an auction for seats on the delivery flight scheduled for June 13, Norwegian says it won't be taking off that day.

"Boeing has informed us that the delivery of our first 737 MAX is postponed until the end of June," the company said in a brief statement.

Why the delay?

Boeing spokesman Doug Alder tells CNBC: "On occasion delivery processes run into minor issues — whether for maintenance or other reasons. In this case, we and our customer decided to re-schedule this delivery in order to resolve a minor technical issue."

Alder declined to give further details about issues causing the delay. Boeing expects Norwegian Air to get the plane by the end of June.

Pushing back scheduled deliveries of new planes is not unusual, but Boeing has a lot riding on its new 737. The transition from the current 737 NG to the 737 MAX is being watched closely.

Boeing is currently building 42 737s each month, with monthly production scheduled to jump to 47 later this year, 52 in 2018 and 59 in 2019. As that production climbs, so will deliveries of the 737 MAX.

There's no indication that delaying some initial 737 Max deliveries will jeopardize Boeing's production plans, but pushing back Norwegian's delivery comes less than a month after Boeing suspended 737 MAX test flights to inspect some of the engines for a potential manufacturing flaw.

After inspecting the LEAP 1B engines and working with the engine manufacturer CFM International, Boeing resumed test flights, and the first 737 MAX 8 was delivered in mid-May to the Asian carrier Malindo Air. Malindo is now operating two 737 MAX planes.

As for Norwegian, the delivery delay will not change the airline's plan to expand service to the U.S. this summer.

"This will not affect our operation or our passengers, as the upcoming launch of transatlantic routes between the U.S. East Coast and Ireland, Northern Ireland, Scotland and Norway will be operated by another aircraft type," the airline said.

Boeing shares closed Friday up more than 1.6 percent at about $190.23.